[gmorphanAt]

I've been autocrossing & time trialing for 38 years and have never heard of a strut tower brace being required for any class. They usually bump you up a class, especially if it triangulates and mounts to the firewall in any way. If a local club or track required it I'd personally want to now what their logic was.

That all being said, I've had them on a number of my cars...especially older Fox bodied 5.0's running in E-Mod. And I'll admit I have a Perrin brace on my '16 WRX now. It is truly not needed and is a waste of money, but I had a weak moment and a $180 in my pocket.

 

[gmorphanAt]

The strut tower bar would be beneficial for the 5.0, particularly the Fox body I'm sure.

I frequently tracked my old Mustangs and since I was already running classes that allowed the strut braces, I ran them.
I felt they, along with sub-frame connectors, were good insurance to keeping my cars more solid in their later years.

But the need for one in a late model WRX is very questionable. The cars already have a fairly rigid chassis.
Can't understand any track or club making a strut tower brace a requirement....on any car.